Chris Filachek Database/TPFDF Subcommittee. AIM Enterprise Platform Software IBM z/transaction Processing Facility Enterprise Edition 1.1.

Transcription

1 z/tpf V1.1 z/tpfdf Multiple LREC Buffers APAR PM55273 Chris Filachek Database/TPFDF Subcommittee AIM Enterprise Platform Software IBM z/transaction Processing Facility Enterprise Edition Any reference to future plans are for planning purposes only. IBM reserves the right to change those plans at its discretion. Any reliance on such a disclosure is solely at your own risk. IBM makes no commitment to provide additional information in the future.

2 Agenda Requirement Description Solution - Multiple LREC Buffers Coding Examples

3 Requirement Description Create copy of z/tpfdf subfile Read selected LRECs from z/tpfdf subfile and copy to a buffer Send/save/etc. the buffer outside of z/tpfdf Receive copy of z/tpfdf subfile and enable for local processing Add LRECs from buffer to subfile Use z/tpfdf APIs to read/update individual LRECs in subfile

4 Reading one LREC at a time z/tpfdf Application Copy DF Read z/tpfdf Library 1. ECB Heap 2. LREC a 3. LREC b 5. LREC z 1. Allocate buffer in ECB heap 2. DF read & copy LREC a 3. DF read & copy LREC b 4. lots of DF reads and copies 5. DF read & copy LREC z Result: Inefficient process due to many API calls

5 Agenda Requirement Description Solution - Multiple LREC Buffers Coding Examples

6 Solution - Multiple LREC Buffers New buffer structure holds multiple LRECs Application defines buffer in ECB heap z/tpfdf controls buffer contents May contain fixed or variable size LRECs or LLRs New C and Assembler APIs Reads multiple LRECs from DF subfile into buffer Adds LRECs in buffer to z/tpfdf subfile Buffer management APIs (initialize, resize, etc.)

7 New z/tpfdf Read APIs Read multiple LRECs from subfile to buffer dfred_multi() DBRED MULTI= Read LRECs using standard search keys or no keys Reads until all selected LRECs are read or buffer is full Buffer dfred_multi() z/tpfdf Library

8 New z/tpfdf Add Key and Add LREC APIs Add LRECs in buffer to subfile dfadd_multi() DBADD MULTI= Adds LRECs at appropriate locations using default keys or add keys Unique keys are supported Define add keys prior to add LREC df_setkey_add() DBSETK #DF_ADD_NEWLREC Determines where in the subfile each new LREC is added Can be used with any z/tpfdf add APIs Only type of setkey supported for multiple LREC add

9 New Buffer Management APIs Initialize the buffer dfmbuf_init() DBMBUF INIT Initializes a new buffer or reinitializes existing buffer Resize the buffer dfmbuf_resize() DBMBUF RESIZE Allows z/tpfdf to use larger buffer after existing buffer is expanded Get buffer information dfmbuf_getinfo() DBMBUF GETINFO Returns buffer information to application Total buffer size, bytes used, bytes free Number of LRECs

10 New SPMs and C Macros for Error Checking DFMULTI_OK Processing completed successfully DFMULTI_NOTHING_READ No LRECs were read into the buffer DFMULTI_INCOMPLETE Buffer full and unable to read all LRECs into buffer DFMULTI_NOTHING_ADDED No LRECs were added to subfile from buffer Note: See z/tpfdf InfoCenter for additional SPMs and C macros for error checking

11 Read LRECs using Multiple LREC Buffers z/tpfdf Application DF Read z/tpfdf Library 1. ECB Heap 2. Multi-LREC Buffer 3. LREC a 3. LREC b 3. LREC z 1. Allocate buffer in ECB heap 2. Initialize buffer for DF multiple LREC use (inline function) 3. DF read multiple LRECs Result: Efficient process to read and copy LRECs in a single z/tpfdf API call

12 Multiple LREC Buffer is NOT a subfile APIs to read/update/insert/etc. individual LRECs are not provided Not intended for direct data manipulation Intended for efficient copy of LRECs Copy is intended to be sent or stored outside of z/tpfdf but I need to read/update/insert/etc. individual LRECs DBCPY and DBSRT - create a local copy of a subfile Add Multiple LREC buffer to local subfile Temporary subfiles W-type memory resident subfile Short term pools

13 Agenda Requirement Description Solution - Multiple LREC Buffers Coding Examples* * Error checking is left out to keep the coding examples simple for purposes of this presentation.

14 Example 1: Loop to Read all LRECs dft_bufs bufsize = 10000; dft_buf *bufptr; bufptr = (dft_buf *)malloc(bufsize); dfmbuf_init(buf_ptr, bufsize); dfred_multi(dffile_ptr, 0, bufptr); while (DFMULTI_INCOMPLETE(dffile_ptr)) { bufsize += 10000; bufptr = realloc(bufptr, bufsize); dfmbuf_resize(buf_ptr, bufsize); dfred_multi(dffile_ptr, 0, bufptr); } 1. Allocate buffer in heap and use dfmbuf_init() to initialize 2. Read as many LRECs as can fit into buffer 3. Check if all LRECs were read 4. If not all LRECs read a. Realloc larger buffer b. Tell z/tpfdf buffer is resized c. Read more LRECs d. Loop to top

15 Example 2: Send buffer to remote system int sockdesc; dft_ubuf bufinfo; dft_buf *bufptr; dfmbuf_getinfo(bufptr, &bufinfo); if (bufinfo.df_mbufucnt > 0) { send(sockdesc, (char *)bufptr, bufinfo.df_mbufudat, 0); } 1. Retrieve data size information 2. Check there are 1 or more LRECs in buffer 3. Send contents of buffer using favorite comms protocol

16 Example 3: Receive buffer from remote system int sockdesc, bufsize = 10000; dft_ubuf bufinfo; dft_buf *bufptr = (dft_buf *)malloc(bufsize); read(sockdesc, (char *)bufptr, DF_MBUF_INITIAL_NAB); 1. Read data into buffer using initial buffer size (header only) dfmbuf_getinfo(bufptr, &bufinfo); if (bufinfo.df_mbufudat > bufsize) { bufsize = bufinfo.df_mbufudat; bufptr = realloc(bufptr, bufsize); } dfmbuf_resize(bufptr, bufsize); 2. Get actual buffer size 3. Realloc buffer as needed. Resize to match actual buffer size read(sockdesc, ((char *)bufptr) + DF_MBUF_INITIAL_NAB, bufinfo.df_mbufudat DF_MBUF_INITIAL_NAB); 4. Read remaining data into buffer starting after header dfadd_multi(dffile_ptr, 0, bufptr); 5. Add multiple lrecs to local subfile

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